1. Field of the Invention
The present invention relates to an anticancer composition, and more particularly, to a pharmaceutical composition for inhibiting cancer, which includes a microRNA-30b, microRNA-133a, or microRNA-202-5p inhibitor as an active ingredient.
2. Discussion of Related Art
Cancer is a disease becoming the most major cause of death over the world, exceeding the death due to heart diseases and cerebrovascular diseases. According to the development of economy and changes in a lifestyle and an eating pattern, a type of occurring disease may be changed and cancer incidence increases, resulting in approximately 7,600,000 persons dying of cancer and 12,660,000 new cancer patients occurring in 2008. Therefore, there is a trend of consistent increases in the occurrence of cancer and a death rate caused by cancer. As the society is developed and the population is aging, it is expected that a burden of cancer occurrence will further increase and a cancer incidence in young people gradually increases due to a genetic cause and stress, and therefore the importance of preventing and treating cancer is further magnified. However, since there is no innovative cancer treating method such as development of an anticancer agent having an excellent effect and no side effect, the development of the innovative cancer treating method is urgently needed.
For example, a method of inhibiting tumor and cancer cell proliferation by limiting supply of oxygen and nutrients is actively being developed. To this end, expression of factors involved in glucose metabolism and angiogenesis among genes of tumors and cancer cells expressed in a hypoxia state and an adaptive mechanism to a surrounding microenvironment are important to understand growth and proliferation of tumors and cancer cells.
MicroRNAs (miRNAs) are small non-coding RNAs inhibiting expression of a gene in post-transcriptional regulation. MicroRNA has a hair pin structure formed of averagely 18 to 25 nucleotides. MicroRNA complementarily binds to a 3′ UTR region of a target gene sequence, thereby inhibiting degradation of mRNA or translation to a protein, and approximately 5000 or more human genes are defined as targets of microRNA. As a result, depending on which target gene is regulated, the functions of microRNA in a living organism are diversified into cell differentiation and proliferation, genesis and metabolic regulation, angiogenesis, cell death, etc., and the importance of the role of microRNA is further emphasized and thus the research on microRNA is actively progressing.
Modified microRNA expression patterns are reported in various types of cancer, and known to be involved in regulation of cancer promoters or cancer suppressors. In addition, it has also been found that microRNA regulates angiogenesis, and a new therapeutic method for inhibiting a vascular disease and cancer through such a mechanism is being proposed. There is an urgent need for developing an anticancer drug for preventing formation of cancer cells in an early stage through a mechanism of regulating expression of cancer-relating genes by microRNA and suppressing angiogenesis induced by cancer.
Meanwhile, PTEN (phosphatase and tensin homologue) is known as a representative tumor suppressor serving as a phosphatase with respect to a cell membrane phospholipid, that is, phosphatidylinositol (3,4,5)-trisphosphate (PIP3). It is known that when PTEN is lost or modified, a PIP3 pathway is excessively activated and thus occurrence of various cancers such as brain cancer, breast cancer, glioma, prostate cancer, endometrial cancer, etc. are stimulated. The loss of PTEN reduces sensitivity to Fas, thereby inducing an autoimmune disease, and causes a genetic disease such as Cowden's disease or Lhermitte-Duclos disease, in addition to the occurrence of tumor. It shows that PTEN can play an important role in brain development as well as inhibition of cancer.
However, a molecular-level action mechanism of PTEN and a target thereof have not been clearly known so far. Accordingly, identification of the action mechanism of PTEN and development of a new drug for specifically regulating the PTEN mechanism are very important in development of an anticancer drug.